Method and apparatus for sending and receiving broadcast service in a digital broadcasting system

ABSTRACT

A method and apparatus for receiving a broadcast service in a digital broadcasting system. The method includes receiving, by a reception unit, related information relevant to a common broadcast service being provided in common in at least two Internet Protocol (IP) platforms, from one of the at least two IP platforms; determining, by a mobility management block, whether a currently received broadcast service is the common broadcast service, based on the related information; and continuously receiving the common broadcast service from a remaining IP platform, except for the one of the at least two IP platforms, when the currently received broadcast service is the common broadcast service.

PRIORITY

This application is a Divisional Application of U.S. application Ser.No. 12/475,007, which was filed in the U.S. Patent and Trademark Officeon May 29, 2009, and claims priority under 35 U.S.C. §119(a) to KoreanPatent Application Serial No. 10-2008-0050521, which was filed in theKorean Intellectual Property Office on May 29, 2008, the content of eachof which are incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a method and apparatus for providing abroadcast service to a terminal while maintaining service continuity ina digital broadcasting system.

2. Description of the Related Art

A Digital Video Broadcasting-Handheld (DVB-H) Convergence ofBroadcasting and Mobile Service (CBMS) system, which is a type ofdigital broadcasting system, provides more convenient functions bycombining digital TV broadcast services, which have excellent mobilereception performance, with other mobile communication services.

Currently, people can enjoy High Definition TV (HDTV)-class imagequality and CD-class audio quality in their homes. However, there is anincreasing demand to enjoy TV services of high image quality even whiletraveling.

DVB-H CBMS, which is a system made for mobile receiving terminalscapable of using mobile communication channels, includes a concept of ahandover supported in cell-based wireless communications like in aconventional mobile communication system. However, a handover inbroadcast networks is distinct from a handover in mobile communicationnetworks that always manage subscribers. More specifically, in mobilecommunication systems, the network manages individual users, andreceives Measurement Reports from the terminals for network management,including a handover. However, in general broadcasting systems,broadcast service providers provide services and contents, but do notmanage all of individual users. That is, the service providers send theinformation for broadcast reception to all users over the broadcastnetwork, but have no user management function. Therefore, the handoverin broadcast networks has a specific technical requirement that isdistinguishable from that of the handover in mobile communicationsystems.

FIG. 1 illustrates an architectural model of CBMS, or architecture of ageneral DVB-H system. Internet Protocol (IP) Datacast over DVB-Hinvolves a collection of entities that work together in order to achievethe required capabilities.

The entities illustrated in FIG. 1 are logical entities, which can beeither physically separated or combined into various units, and thelogical entities may be merged into one or more physical entities. Forconvenience purpose, only the interfaces directly associated with themain features of the present invention are illustrated herein.

The system illustrated in FIG. 1 is for Digital VideoBroadcasting-Convergence of Broadcasting and Mobile Service (DVB-CBMS),which is one of the mobile broadcast terminal standard organizations.Although the following description will be given in connection with, forexample, a notification broadcasting mechanism of DVB-CBMS, a similaroperation would also be available in other mobile broadcasting systemswith a notification messaging function.

Referring to FIG. 1, a Content Creation (CC) 110 provides broadcastservices, which may include a conventional audio/video broadcastservice, file (music file or data file) download service, etc. TheContent Creation 110, when there is a problem or change in provision ofbroadcast services, notifies the change to a notification eventgenerator (not shown) in a Service Application (SA) 120.

The Service Application 120 is provided with content data for broadcastservices from the Content Creation 110, and generates broadcast servicedata by processing the content data in a form appropriate for abroadcast network (e.g., in a form of streaming audio/video, moviedownload, etc.). Further, the Service Application 120 createsstandardized metadata needed for an Electronic Service Guide (ESG), andcreates accounting information for users. Also, the Service Application120 receives a notification on the change in broadcast services from theContent Creation 110, delivers a notification event to a notificationmessage generator located in a Service Management (SM) 130, and providesservice guide attribute information used for creation of a notificationmessage to the notification message generator.

The Service Management 130 determines a transmission schedule of thebroadcast services provided from the Service Application 120, andgenerates a service guide. The Service Management 130 is connected to aBroadcast Network 140 capable of providing broadcast services, and anInteractive Network 150 capable of supporting interactive communication.

The Service Management 130 manages subscription information for asubscriber(s) intending to receive a broadcast service, serviceprovision information such as information about whether the subscriberhas purchased relevant contents, and device information for theterminals that will receive the broadcast service. The ServiceManagement 130 delivers user accounting information to the ServiceApplication 120, and provides the subscription information, the serviceprovision information, the device information, etc., to the BroadcastNetwork 140 and the Interactive Network 150.

The Broadcast Network 140 is a network that delivers broadcast services.In this specification, DVB-H will be given as an example of the network.

The Interactive Network 150 delivers broadcast services on a one-to-onebasis, or exchanges control information related to receipt of broadcastservices and additional information in an interactive way, and can beembodied by an existing cellular network such as, for example, a 3GPPWideband Code Division Multiple Access (WCDMA) network.

A Terminal 160 receives broadcast services, and can connect with acellular network according to its capability. In the presentapplication, a terminal capable of accessing the cellular network willbe considered.

CBMS-x is an interface in the scope of the IP Datacast standard overDVB-H, and X-x is an interface out of the scope of the IP Datacaststandard over DVB-H. More specifically, a CBMS-7 interface is aninterface from the Service Application 120 to the Service Management130, and a CBMS-3 interface is used when a message is directly deliveredfrom the Service Management 130 to the Terminal 160 over the BroadcastNetwork 140. A CBMS-4 interface is used when a message delivered fromthe Service Management 130 is directly delivered to the Terminal 160through a dedicated channel to the Terminal 160 over the InteractiveNetwork 150, or through a broadcast channel provided by the InteractiveNetwork 150. A CBMS-6 interface is an interface between the ServiceManagement 130 and the Broadcast Network 140, which is used to establisha transmission path that the Service Management 130 will use in theBroadcast Network 140, or is used as a reception path for eventinformation generated in the Broadcast Network 140. A CBMS-1 interfacecarries control information of the broadcast network to the Terminal160, and a control signal channel, called Program SpecificInformation/Service Information (PSI/SI), corresponds to this interfacein DVB-H.

An X-3 interface is used to establish a transmission path to be usedbetween the Service Management 130 and the Interactive Network 150. AnX-2 interface is used to establish a transmission path to be usedbetween the Terminal 160 and the Interactive Network 150. An X-1interface is used to establish a transmission path to be used betweenthe Content Creation 110 and the Service Application 120.

If a user belonging to a DVB-H network has traveled from an existingnetwork to a neighboring network, or has moved from a current IPplatform to another IP platform, the ongoing service should be providedto the user seamlessly in the network or IP platform to which the userhas moved. A terminal should find the program the user was viewingbefore the handover, from the network to which the user has moved, inorder for the terminal to continuously receive the service. That is,when a transport stream is changed, the terminal should find a transportstream in which the same service is provided, in the network or IPplatform to which the user has moved, and when a transmission frequencyis changed, the terminal should detect frequency information of theneighboring network or IP platform. Information necessary for the aboveprocess may be acquired from PSI/SI provided by a DVB broadcast network.In this case, because the handover procedure and method departs from thescope of the present invention, a detailed description thereof is notprovided. For more details, reference can be made to ETSI TR 101 211Digital Video Broadcasting (DVB); Guidelines on implementation and usageof Service Information (SI).

In the above-described process, a service identifier may play animportant role in finding the program the user is viewing. The steps theterminal takes to receive the program even after the handover may alsobe applied in the same way if the user makes inter-cell movement andinter-subcell movement. In addition, when the network or IP platform towhich the user has moved does not support the service the user wasviewing before, the terminal checks if there is any alternative serviceavailable in that network or IP platform. Here, “alternative service”refers to, for example, a new service that is different in programorganization in each region, but of the same genre.

The above-described IP platform, which is a set of IP flows managed bythe service providers, represents a harmonized IP address space that hasno address collisions. An IP platform may span several transport streamswithin one or more networks. Several IP platforms may co-exist in thesame transport stream. An IP platform is identified by platformidentification (id).

Platform id values are divided into two ranges. One range includesplatform id values that are globally unique. Another range includesplatform id values unique only within the scope of a DVB network. Suchan IP platform id is globally and uniquely identified by onlycombination of both a platform id and a network id. In thespecification, for ease of description, the first case that globalunique platform id is to be used as an example.

In the current network, each IP platform is independent. The IP flowsfrom different IP platforms are also independent, and their IP addresseshave no interrelationship. For example, two IP flows in different IPplatforms have the same IP address, but they may be different IP flowsbecause two IP platforms are totally independent.

As described above, there is a problem about service continuity in adigital broadcasting system such as DVB-H CBMS. When the same broadcastservice exists in the different IP platforms, the terminal cannotrecognize it is the same broadcast service because its IP address indifferent IP platforms is independent. Therefore, when the terminalchanges reception of the broadcast service from a first IP platform to asecond IP platform, it cannot continue to receive the broadcast serviceeven though the same broadcast service exits in both of the first andsecond IP platforms.

SUMMARY OF THE INVENTION

Accordingly, the present invention is designed to address at least theabove-mentioned problems and/or disadvantages and to provide at leastthe advantages described below.

An aspect of the present invention provides a method and apparatus forsending and receiving a broadcast service in a digital broadcastingsystem.

Another aspect of the present invention provides a method and apparatusfor sending and receiving a broadcast service while maintaining servicecontinuity in a digital broadcasting system.

In accordance with an aspect of the present invention, there is provideda method for receiving a broadcast service in a digital broadcastingsystem. The method includes receiving related information relevant to acommon broadcast service being provided in common in at least twoInternet Protocol (IP) platforms, from one of the at least two IPplatforms; and determining whether a currently received broadcastservice is the common broadcast service, based on the relatedinformation, and continuously receiving the common broadcast servicefrom a remaining IP platform except for the one IP platform when thecurrently received broadcast service is the common broadcast service.

In accordance with another aspect of the present invention, there isprovided an apparatus for receiving a broadcast service in a digitalbroadcasting system. The apparatus includes a reception unit forreceiving related information relevant to a common broadcast servicebeing provided in common in at least two Internet Protocol (IP)platforms, from one of the at least two IP platforms; and a mobilitymanagement block for determining whether a currently received broadcastservice is the common broadcast service, based on the relatedinformation, and controlling the reception unit to continuously receivethe common broadcast service from a remaining IP platform except for theone IP platform when the currently received broadcast service is thecommon broadcast service.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other aspects, features, and advantages of certainembodiments of the present invention will be more apparent from thefollowing description taken in conjunction with the accompanyingdrawings, in which:

FIG. 1 illustrates an architectural model of CBMS, or architecture of ageneral DVB-H system;

FIG. 2 illustrates a platform id according to an embodiment of thepresent invention;

FIG. 3 illustrates a structure of a platform id when a plurality of IPplatforms exists and the IP platforms are cooperating IP platforms,according to an embodiment of the present invention;

FIG. 4 illustrates an IP address range for broadcast services when twocooperating IP platforms exist, according to an embodiment of thepresent invention;

FIG. 5 illustrates an IP address range for broadcast services when twocooperating IP platforms have the same IP address range, according to anembodiment of the present invention;

FIG. 6 illustrates an IP address range for ESG services when differentESGs are provided in cooperating IP platforms according to further anembodiment of the present invention;

FIG. 7 illustrates different ESG FLUTE sessions for the current andcooperation IP platforms based on cooperating ESGs according to anembodiment of the present invention;

FIG. 8 illustrates possible assignment of different entry points for theESG fragment in the current IP platform and the common service-relatedESG fragment in a cooperating IP platform based on cooperating ESGsaccording to an embodiment of the present invention;

FIGS. 9A and 9B illustrate an operation of a terminal according to anembodiment of the present invention;

FIG. 10 illustrates an operation of a service provider in a broadcastingsystem according to an embodiment of the present invention;

FIG. 11 illustrates architecture of a digital broadcasting systemaccording to an embodiment of the present invention; and

FIG. 12 illustrates a structure of a terminal according to an embodimentof the present invention.

Throughout the drawings, the same drawing reference numerals will beunderstood to refer to the same elements, features and structures.

DETAILED DESCRIPTION OF EMBODIMENTS THE PRESENT INVENTION

Hereinafter, various embodiments of the present invention will bedescribed in detail with reference to the accompanying drawings. In thefollowing description and drawings, a detailed description of knownfunctions and configurations incorporated herein will be omitted when itmay obscure the present invention in non-essential details.

The terms and words used in the following description and claims are notlimited to the bibliographical meanings, but are merely used by theinventor to enable a clear and consistent understanding of theinvention. Accordingly, it should be apparent to those skilled in theart that the following description of the embodiments of the presentinvention are provided for illustration purpose only and not for thepurpose of limiting the invention as defined by the appended claims andtheir equivalents.

In the following description, different IP platforms may provide thesame broadcast service, and each of the different IP platforms thatcooperate with each other to provide the same broadcast service will bereferred to as a “cooperating IP platform.” Herein, the same IP addressis assigned to the same broadcast service in all cooperating IPplatforms. Accordingly, if the terminal finds the same IP address indifferent IP platforms, that the terminal can identify that the sameservice exists in different IP platforms. Consequently, the terminal cancontinue to receive the broadcast service even when it changes thereception from one IP platform to another.

In embodiments of the present invention described hereinbelow, differentIP platforms cooperate with each other to assign the same IP addressrange for the same broadcast services, and a mobile terminal may findthe same broadcast service from the different cooperating IP platformsto continuously receive the broadcast service. For example, if an IPplatform A also provides a broadcast service A while an IP platform Bprovides the broadcast service A, and the broadcast service A providedin the IP platform A and the broadcast service A provided in the IPplatform B have the same IP address, then the IP platforms A and B willbecome cooperating IP platforms. That is, when the IP platform A ispresently receiving the broadcast service A, the IP platform B becomes acooperating IP platform for the IP platform A, and vice versa.

To support the cooperating IP platforms, the following mechanism may beproposed.

1. Indicating if IP Platforms Share a Common IP Address Range

The sharing (or cooperating) relationship between IP platforms should beindicated.

To indicate the relationship between IP platforms, the cooperatingplatform identifier (id) may be assigned to these cooperating IPplatforms.

FIG. 2 illustrates a platform id according to an embodiment of thepresent invention. Referring to FIG. 2, a platform id length is dividedinto two parts as. In the platform id, a first part 200 is a part whereall IP platforms have the common value when an IP platform shares an IPaddress range with other IP platforms, and a second part 202 is areserved part used to identify each IP platform.

A partial range of an IP address of each IP platform is set as a commonIP address range for the services that respective IP platforms providein common, so the terminal may check if the respective IP platforms havethe common IP address range, and then determine if the same broadcastservice is provided in common in different IP platforms.

FIG. 3 illustrates a structure of a platform id when a plurality of IPplatforms (IP platform 1 and IP platform 2) exist and the IP platformsare cooperating IP platforms, according to an embodiment of the presentinvention.

A Platform id in FIG. 3 has a common part, or ‘11111’, as indicated byreference numeral 300. Here, ‘11111’ is set as a common value becausethe IP platform 1 and the IP platform 2 are cooperating IP platformsthat can both provide the same broadcast service. Reference numeral 302indicates bits used to identify the respective IP platforms.

The accurate numbers of bits in the parts 300 and 302 are not defined inthe present invention.

Alternatively, the cooperating relationship could also be signaled tothe terminal through notification, ESG, PSI/SI or provisioning, or anyother signaling.

Table 1 below shows parameters for signaling of cooperating IP platformsaccording to an embodiment of the present invention. For example, theseparameters can be signaled to the terminal through notification, ESG,PSI/SI or provisioning, or any other signaling.

TABLE 1 Field Semantics signaling about cooperating IP Specifies inBoolean value whether this platform identifier IP platform has an IPaddress range in common with other IP platforms. No_IPPlatform Specifiesa number assigned to the cooperating IP platform Platform id Specifiesthe identifier of the cooperating IP platform

Reference numerals 200 and 300 indicate No_IPPlatform in Table 1, andreference numerals 202 and 302 indicate Platform id in Table 1.

The parameters described in Table 1 may be used flexibly. For example,in the PSI/SI, there is one element about a platform provider name. Forone group of cooperating IP platforms, this information may be indicatedinside the platform provider name. Here, “one group of cooperating IPplatforms” means a bundle of cooperating IP platforms, which are IPplatforms that assign the same broadcast service to the same IP address.

Reference numeral 200 in FIG. 2 indicates No_IPPlatform in Table 1. TheNo_IPPlatform indicates one group of cooperating IP platforms. If IPplatforms in one group are cooperating IP platforms, all IP platforms inthis group will have the same No_IPPlatform as indicated by referencenumeral 200. FIG. 3 illustrates an example of one group of cooperatingIP platforms. In this example, all IP platforms in this one group have0x11111 as No_IPPlatform as indicated by reference numeral 300.

Reference numeral 202 in FIG. 2 is used to identify each IP platform inthe one group, or the bundle of cooperating IP platforms. Regardingreference numeral 302 in FIG. 3, it can be noted that 16 IP platforms(0˜F) may exist in one group of cooperating IP platforms. “0x11111”indicated by reference numeral 300 is used to distinguish thiscooperating IP platform group from another cooperating IP platformgroup, and each IP platform in the cooperating IP platform group has acommon part indicated by reference numeral 300. In this way, referencenumeral 300 shows that the 16 IP platforms included in the cooperatingIP platform group have the same No_IPPlatform, meaning that the 16 IPplatforms belong to the same group of cooperating IP platforms. A valueof reference numeral 302 is used to identify each IP platform includedin the cooperating IP platform group.

2. IP Address for the Same Service in Cooperating IP Platforms

The IP addresses used in the cooperating IP platforms may be dividedinto different ranges: one range corresponding to the same broadcastservice as that provided in common in different IP platforms in thecooperating IP platform group, and another range corresponding todifferent broadcast services provided in different IP platforms.

FIG. 4 illustrates an IP address range for broadcast services when twocooperating IP platforms (IP platform 1 and IP platform 2) exist,according to an embodiment of the present invention. Referring to FIG.4, the IP address range, when two cooperating IP platforms (IP platform1 and IP platform 2) exist, can be divided into an IP address range forthe broadcast services existing only in the IP platform 1 out of thecooperating IP platforms, an IP address range for the broadcast servicesexisting in both the IP platform 1 and the IP platform 2, and an IPaddress range for the broadcast services existing only in the IPplatform 2.

Reference numeral 400 indicates an IP address range for the broadcastservices provided in the IP platform 1, and reference numeral 410indicates an IP address range for the broadcast services provided in theIP platform 2. The term “IP address range” as used herein means an IPaddress range in which IP addresses for the broadcast services areincluded. For example, when an IP address of a specific broadcastservice is 198.122.12.1, IP addresses of the broadcast service, rangingfrom 198.122.12.1 to 198.122.12.16, can be considered as the IP addressrange. That is, the same IP address is assigned to the broadcastservices provided in common in the IP platform 1 and the IP platform 2which are cooperating IP platforms, and the same IP address range willbe assigned to at least two broadcast services provided in common in thecooperating IP platforms.

As illustrated in FIG. 4, two cooperating IP platforms are considered byway of example. The IP address used in these two IP platforms is dividedinto three ranges. A first range 402 is used for the broadcast servicethat exits only in the IP platform 1, a third range 406 is used for thebroadcast service that exits only in IP platform 2, and a second range404 (an overlapping range in both IP platforms) is used for the commonbroadcast service that exits in both the IP platform 1 and the IPplatform 2. That is, reference numeral 400 a indicates an IP addressrange for the broadcast services existing only in the IP platform 1,reference numeral 410 b indicates an IP address range for the broadcastservices existing only in the IP platform 2, and reference numerals 400b and 410 a indicate IP address ranges for the broadcast servicesexisting in common in both the IP platform 1 and the IP platform 2.Based on the example of FIG. 4, if the terminal detects the same IPaddress in the both IP platforms, it is able to identify that the sameservice is found in these two IP platforms.

As another example, two cooperating IP platforms have the same IPaddress range.

FIG. 5 illustrates an IP address range for broadcast services when twocooperating IP platforms have the same IP address range, according to anembodiment of the present invention.

Referring to FIG. 5, the IP address range, when two cooperating IPplatforms have the same IP address range, can be divided into an IPaddress range for the broadcast services existing only in the IPplatform 1 or the IP platform 2 out of the cooperating IP platforms, andan IP address range for the broadcast services existing in both the IPplatform 1 and the IP platform 2.

The common IP address range for the common broadcast services providedin both cooperating IP platforms is reserved, and others are IP addressranges for the non-common broadcast services. In this case, which rangeis used for common broadcast services in all cooperating IP platformsshould be provisioned or signaled to the terminal. In this embodiment,with the information in Table 2, the terminal can identify whether theservice is the same service or different one when it detects the same IPaddress in different IP platforms.

FIG. 5 illustrates an IP address range for the broadcast servicesexisting only in the IP platform 1 or the IP platform 2, and an IPaddress range for the broadcast services existing in both the IPplatform 1 and the IP platform 2 in accordance with an embodiment of thepresent invention. More specifically, reference numeral 500 in FIG. 5indicates an IP address range of the IP platform 1, and referencenumeral 510 indicates an IP address range of the IP platform 2.Reference numeral 520 indicates an IP address range for the broadcastservices existing only in the IP platform 1 or the IP platform 2, andreference numeral 530 indicates an IP address range for the broadcastservices existing in both the IP platform 1 and the IP platform 2.

Parameters about the IP address range for the common broadcast servicesin cooperating IP platforms as illustrated in FIG. 5 are shown in Table2. The information in Table 2 may be signaled using notification, ESG,PSI/SI, independent signaling, provisioning, etc.

TABLE 2 Field Semantics Signaling about IP address range Specifies thatthis signaling is for for the common broadcast service indicating the IPaddress range for the exiting in the cooperating IP common broadcastservice exiting in platform the cooperating IP platform Start_IPAddressSpecifies the start IP address of the range for the common broadcastservice in the cooperating IP platform End_IPAddress Specifies the endIP address of the range for the common broadcast service in thecooperating IP platform

Referring to FIG. 5, because reference numeral 540 indicates a startpart of an IP address corresponding to the common broadcast services inthe IP platform 1 and the IP platform 2 which are cooperating IPplatforms, reference numeral 540 becomes the start IP addressStart_IPAddress in Table 2. Similarly, because reference numeral 550indicates an end part of the IP address corresponding to the commonbroadcast services in the IP platform 1 and the IP platform 2, referencenumeral 550 becomes the end IP address End_IPAddress in Table 2. Whenthe number of the common IP address ranges is plural, the number of setsof Start_IPAddress and End_IPAddress could also be plural.

3. Cooperating ESG Mechanism

Based on the current ESG specification, ESGs in different IP platformsshould be different. FIG. 6 illustrates an example in which IP platformshave different ESGs. For example, an ESG1 600 is provided in the IPplatform 1, and an ESG2 650 is provided in the IP platform 2. Thisexample is based on the first cooperating IP platforms as describedabove, although a similar example could also be based on of the secondcooperating IP platforms as described above.

The same broadcast services provided in these two IP platforms have thesame IP address range. However, the information related to the samebroadcast service, e.g., schedule, purchase, and acquisition, may beeither same or different for the respective IP platforms. Accordingly,the related fragments in ESG1 and ESG2 for the same services may also bethe same or different.

Reference numeral 600 a in FIG. 6 indicates an IP address range for thebroadcast services provided by the ESG1 600 provided in the IP platform1, and reference numeral 650 a indicates an IP address range for thebroadcast services provided by the ESG2 650 provided in the IP platform2. Reference numeral 610 indicates an IP address range for the broadcastservices provided by an ESG provided only in the IP platform 1,reference numeral 620 indicates an IP address range for the broadcastservices provided by ESGs provided in common in both the IP platform 1and the IP platform 2, and reference numeral 630 indicates an IP addressrange for the broadcast services provided by an ESG provided only in theIP platform 2.

3.1 Signaling of Common Service in ESG

To indicate which service in the ESG is the common service provided inthe cooperating IP platforms, a new element may exist in a servicefragment (or in any other location) as shown in Table 3. The servicefragment is a field existing in the ESG. That is, the ESG includes a setof data structures, including a service fragment containing overallinformation such as an id of the service provided, a content fragmentcontaining attribute information such as a codec for the content orvideo and audio constituting each service, a schedule event fragmentindicating the time the service is to be provided, an access fragmentproviding a location of the server where the service can be accessed, aservice purchase fragment, and a purchase channel fragment. Therefore,‘CommonServiceInCooperationIPPlatform’ (indicating a common service inthe cooperating IP platform) as proposed in Table 3 is an element addedin the service fragment, but its location should not be limited to aparticular fragment.

TABLE 3 Field Semantics CommonServiceInCooperationIP If it is set to“true,” the attribute Platform specifies that the service is the commonservice in cooperating IP platform. If it is set to “false,” theattribute specifies that the broadcast service is not the common servicein cooperating IP platform.

3.2 Identical ESG Fragment for the Common Broadcast Service inCooperating IP Platform

To support service continuity, all the information about the sameservice could be the same. Therefore, the fragment related to the sameservice in ESG1 and ESG2 is also the same.

In this case, if the terminal changes a reception path for the samebroadcast service from the IP platform 1 to the IP platform 2, it doesnot need to newly access the ESG2 to receive the same broadcast servicein the IP platform 2, but only needs to use the related informationdescribed in the ESG1. After the terminal parses an IP/MAC NotificationTable (INT) table for the IP platform 2 from the ESG1 received from theIP platform 1, could the terminal may access the service from the IPplatform 2.

3.2.1 New Aignaling AboutIdenticalInformationForCommonServiceInCooperationIPP latform

Because the same broadcast services provided in the cooperating IPplatforms have the same IP address, the terminal can find the samebroadcast service in different cooperating IP platforms by checking thesame IP address. However, the same broadcast service in different IPplatforms may have different schedule, purchase, acquisition and otherinformation in each related ESG. That is, even if the service contentsare the same, the service description information, schedule, accessserver information, purchase server information, etc., may be differentdepending on the service provider. When this information is different,only the information in Table 3 of the invention is provided, and whenall the information related to the services provided in the ESG is thesame, information of Table 4 is provided.

More specifically, to indicate that the identical ESG fragment is usedfor same service in two cooperating IP platforms, additional signalingis needed as shown in Table 4. In this case, it should be set as “true.”The information of Table 4 is delivered through the ESG.

The information in Table 3 indicates whether the current broadcastservice is a common service or not in another IP platform. If the‘CommonServiceInCooperationIPPlatform’ field of Table 3 is set as‘true’, it means that the current broadcast service is the commonservice in the cooperating IP platforms.

The information in Table 4 below indicates whether the identical ESGfragment is used or not for such common broadcast service. If the‘IdenticalInformationForCommonServiceInCooperationIPPlatform’ field inTable 4 is set as ‘true’, it means that the identical ESG fragment isused for the common broadcast service. If the field of Table 4 is set as‘false’, it means that another ESG fragment is used for the commonbroadcast service.

Therefore, if the field of Table 3 is set to ‘true’, the field of Table4 could be set as either ‘true’ or ‘false’. However, if the field ofTable 3 is set to ‘false’, the field of Table 4 is useless.

TABLE 4 Field Semantics IdenticalInformationForCommon If it is set to“true,” the attribute ServiceInCooperationIPPlatform specifies that theESG fragment for the common service in cooperating IP platform isidentical. If it is set to “false,” the attribute specifies that the ESGfragment for the common service in cooperating IP platform is different.

For example, it is assumed that one group of cooperating IP platformshas ten (10) IP platforms. If the identical ESG fragment for the commonbroadcast service is used in every IP platform in this group, thesignaling in Table 3 is sufficient. If the identical ESG fragment forthe common broadcast service is used in only the IP platform 1 and theIP platform 2 in this group, then which IP platform is applied should beindicated as in Table 5. The information of Table 5 delivered throughthe ESG.

TABLE 5 Field Semantics IdenticalInformationForCommon If it is set to“true,” the attribute ServiceInCooperationIPPlatform specifies that theESG fragment for the common service in cooperating IP platform isidentical. If it is set to “false,” the attribute specifies that the ESGfragment for the common service in cooperating IP platform is different.Platform_id Specifies the identifier of the IP platform that theidentical ESG fragment for the common service is used.

3.2.2 Definition of Location of the New Signaling AboutIdenticalInformationForCommonServiceInCooperationIPPlatform field andPlatform_id field in Table 5

The signaling locations about these fields may vary.

If an ESG fragment for all the common services described in one ESG isidentical in all cooperating IP platforms, theIdenticalInformationForCommonServiceInCooperationIPPlatform field andthe Platform_id field could be added in the bootstrap level fordescribing the attribute of this ESG, or ESG announcement carousel.

If the signaling as shown in Table 5 is used for each broadcast service,Table 5 could be put in the service fragment as a new element ordescriptor.

Table 5 may also be added in PSI/SI, notification, etc.

3.3 Different ESG Fragment for the Common Broadcast Service inCooperating IP Platforms

The different ESG fragments for the common broadcast service, e.g.,purchase fragment, schedule fragment, acquisition fragment, etc., inanother cooperating IP platform could be also delivered in the currentIP platform. Accordingly, the terminal has ESG information about thecommon broadcast service in cooperating IP platforms without accessingthat IP platform.

The delivery of different ESG fragments for the common service for theother cooperating IP platforms in the current IP platform may beperformed in variety of way. One possible method is described below.

3.3.1 Different ESG File Delivery Over Unidirectional Transport (FLUTE)Session for the Current and Cooperating IP Platforms

FIG. 7 illustrates different ESG FLUTE sessions for the current andcooperation IP platforms based on cooperating ESGs according to anembodiment of the present invention.

As illustrated FIG. 7, different ESG FLUTE sessions may be used totransport the ESG fragment for the current IP platform, and the ESGfragment for the cooperating IP platforms (cooperating IP platform 1 andcooperating IP platform 2) that can provide the same broadcast serviceas that of the current IP platform. An ESG announcement carousel FLUTEsession 700 includes a File Delivery Table (FDT) instance 701, an ESGInitiation (Init) Container 702, and ESG Index Containers 703 to 704.

A first FLUTE session 750 is used for delivering an ESG fragment in thecurrent IP platform, and other FLUTE sessions 760 to 770 are used forthe common service-related fragments in the other IP platforms(cooperating IP platform 1 and cooperating IP platform n).

TOI in FIG. 7 indicates a Transport Object Identifier in Layered CodingTransport (LCT). The ESG Init Container 702 includes a Container Header711, an ESG Init Message 712, an ESG Partition Declaration 713, an Index714, and an Index Structure 715. The Container Header 711 describes astructure type and an id in the container.

The ESG Init Message 712 initializes reception of the ESG. For thispurpose, a representation of the ESG, an index, and a presence ofdecoder Init are signaled.

The Index Structure 715 announces a set of indexes available in the ESGstream. The Index Structure 715 declares global settings for the index,or declares a range of values discoverable within given sub-indexes anda set of sub-indexes constituting the index. The ESG PartitionDeclaration 713 particularly describes a partitioning strategy, andinforms the terminal how the ESG is partitioned and what partitioningcriteria is used in every session.

New partitioning mechanisms may be provided to distinguish the differentESG fragments for different IP platforms as in Table 6.

Referring to FIG. 7, an ESG may be divided into a plurality of FLUTEsessions according to partitioning mechanism. When ‘0x00’ in Table 6 isused as a partitioning rule, it indicates that each FLUTE session of theESG is partitioned and delivered according to the time for whichservices included in the ESG are provided. Reference numeral 750indicates a FLUTE session for the current IP platform, reference numeral760 indicates a FLUTE session for the cooperating IP platform 1, andreference numeral 770 indicates a FLUTE session for the cooperating IPplatform n.

If ‘n’ is ‘2’, the ESG will be partitioned into FLUTE sessions for 3 IPplatforms and then delivered through them. That is, an ESG including theservices to be provided for the next 24 hours is partitioned into threeparts: 0-8 o'clock, 9-16 o'clock and 17-24 o'clock, and then deliveredthrough the FLUTE sessions 750, 760 and 770, respectively. Thus, inaccordance with an embodiment of the present invention a rule forpartitioning the FLUTE sessions according to IP platforms is added.

TABLE 6 Value Encoding Meaning 0x00 0x0101 (unsigned The number of hoursfor which the fragments short integer) are valid. This may be used tosplit the ESG into various schedule depths. 0x01 0x0000 (string) The URIof the Service fragments ServiceID. This may be used to carry allfragments relevant to a particular service. 0xA0 0x0101 (positivePlatform id Integer)

The ESG Partition Declaration 713 includes a field identifier indicatingwhich partition criteria is used, and a start_field_value and anend_field_value for each FLUTE session, which represent a range valuefor an IP address about each FLUTE session. If there are no range valuesoverlapping between FLUTE sessions, the end_field_value will be omitted.

When a new criterion for the “platform id” is used, the field identifieris set as 0XA0 in the ESG Partition Declaration 713. In FIG. 7, thefirst FLUTE session 750 is for the current IP platform, and astart_field_value of this session is set as a platform id of the currentIP platform. An end_field_value may be omitted. The second FLUTE session760 is for a cooperating IP platform 1 cooperating with the current IPplatform, and a start_field_value of this session is set as a platformid of the cooperating IP platform 1. The n^(th) FLUTE session 770 is fora cooperating IP platform n cooperating with the current IP platform,and its start_field_value is set as a platform id of the cooperating IPplatform n.

In FIG. 7 illustrates an IP address where each FLUTE session begins isassigned 5 on a platform-by-platform basis through the ESG PartitionDeclaration 713 as indicated by reference numeral 720. An IP address 720a of the ESG FLUTE session for the current IP platform as indicated byreference numeral 750, an IP address 720 b of the FLUTE session for thecooperating IP platform 1, and an IP address 720 c of the FLUTE sessionfor the cooperating IP platform n are entry points of the respectiveFLUTE sessions.

3.3.2 Different ESG Entry Points for the Current and Cooperating IPPlatforms

FIG. 8 illustrates possible assignment of different entry points for theESG fragment in the current IP platform and the common service-relatedESG fragment in a cooperating IP platform based on cooperating ESGsaccording to an embodiment of the present invention. Reference numeral850 in FIG. 8 identifies an ESG Announcement Carousel FLUTE Session forthe current IP platform, and reference numeral 860 shows an ESGAnnouncement Carousel FLUTE Session for a cooperating IP platform.

An ESG Bootstrap 800 includes an FDT Instance 801, an ESG ProviderDiscovery Descriptor 802, and an ESG Access Descriptor 803. Thedescriptors provide the information for acquisition of the ESG Providerand available ESGs. Referring to FIG. 8, the ESG Provider defines an ESGprovider that delivers an ESG in a given IP platform. The ESG AccessDescriptor 803 is a binary number indicating ESG acquisitioninformation.

In FIG. 8, one ESG has one or more entry points. One entry point carriesan ESG announcement carousel FLUTE session 850 for the current IPplatform. This entry point is indicated using a platform id of thecurrent IP platform.

Another entry point carries an ESG announcement carousel FLUTE session860 for an IP platform cooperating with the current IP platform. Thisentry point is indicated using a platform id of the cooperating IPplatform.

This new element “Platform id” may be added in the ESG Access Descriptor803 in various ways. The “Platform id” in Table 7 or Table 8 indicatesfor which IP platform the entry points are to be used. However, this isa mere example, and for a detailed description of the other elements,reference could be made to ETSI TS 102 471. Tables 7 and 8 below showthe insertion of the Platform id into the ESG Entry or ESG AccessDescriptor according to an embodiment of the present invention.

In an embodiment of the present invention, an entry point of an IPplatform corresponding to the Platform id may be carried in the ESGEntry of Table 7 or the ESG Access Descriptor of Table 8.

The Platform id could be added in various locations in the ESG AccessDescriptor. Table 7 shows one possible location, and Table 8 showsalternative possible locations.

TABLE 7 Syntax ESGEntry { ESGEntryVersion ESGEntryLengthMultipleStreamTransport IPVersion6 Reserved ProviderID if(IPVersion6) {SourceIPAddress DestinationIPAddress }else{ SourceIPAddressDestinationIPAddress } Port TSI Platform id }

TABLE 8 Syntax ESG Access Descriptor { n_o_ESGEntries for(i=0;i<n_o_ESGEntries; i++) { ESGEntry[i]( ) Platform id } }

3.3.3 Different ESGs for the Current and Cooperating IP Platforms

If the different ESGs for the common broadcast service in cooperating IPplatforms are delivered in the current IP platform, the signaling of IPplatform identifier for each ESG is included in the bootstrap level asshown in Table 9 below. The location may be in the existingESGProviderDiscoveryDesriptor and ESGAccessDescriptor, or newdescriptors.

TABLE 9 Field Semantics ESGURI Specifies the ESG identifier Platform idSpecifies the platform identifier that is associated to the ESG.

FIGS. 9A and 9B illustrate an operation of a terminal according to anembodiment of the present invention.

In step 900, the terminal receives PSI/SI and selects an IP platform 1for a bootstrap. In step 902, the terminal accesses an ESG1 from the IPplatform 1.

In step 904, the terminal selects a broadcast service 1 in the ESG1, anddetermines if a CommonServiceInCooperationIPPlatform field is set as“true” in the received ESG1. If the CommonServiceInCooperationlPPlatformfield is set as “true,” the terminal determines that the broadcastservice 1 is a common service. In step 906, the terminal receives thebroadcast service 1 in the IP platform 1.

However, in step 908, the terminal could not receive the broadcastservice from the IP platform 1 for several reasons, such as a reason forleaving the coverage of the IP platform 1 as it moves to an IP platform2. Because, however, it is determined in step 904 that theCommonServicelnCooperationlPPlatform field is set as “true,” theterminal could know the IP platform 2 is an IP platform cooperating withthe IP platform 1 based on the Platform id as shown in Table 5, knowingthat the broadcast service 1 is the common service in the cooperating IPplatforms.

In step 910, the terminal may identify whether the same information asthe information needed to receive the broadcast service 1 is availablein the IP platform 2 cooperating with the IP platform 1, by checking avalue of an IdenticalInformationForCommonServiceInCooperationIPPlatformfield included in the ESG1 from the IP platform 1. TheIdenticalInformationForCommonServiceInCooperationIPPlatform field isincluded in the ESG1 received from the IP platform 1.

If the IdenticalInformationForCommonServiceInCooperationIPP latformfield value is set as “true” in step 912, the terminal determines instep 914 that the identical ESG information as the ESG information forthe broadcast service 1 exists in the IP platform 2 cooperating with theIP platform 1. In step 916, the terminal searches access information ofthe IP platform 2 in the current PSI/SI received from the IP platform 1or scans neighboring signaling, and searches access information for thebroadcast service 1 provided in the IP platform 2. Thereafter, in step918, the terminal changes its broadcast service reception path byperforming a handover from the IP platform 1 to the IP platform 2, andaccesses the broadcast service 1 provided from the IP platform 2 toreceive the same broadcast service as the broadcast service that wasprovided from the IP platform 1.

However, if it is determined in step 912 that theIdenticallnformationForCommonServicelnCooperationlPPlatform field'svalue is set as “false,” the terminal determines in step 920 that theESG information for the broadcast service 1 existing in the IP platform2 is different from the ESG information for the broadcast service 1 thatwas provided in the IP platform 1. In step 922, the terminal collectsESG fragments different from those of the IP platform 1 for thebroadcast service 1 in the IP platform 2 cooperating with the IPplatform 1, from another ESG FLUTE session, entry point and even anotherESG. In step 924, the terminal may need different purchase or accessschedule from that of the IP platform 1, when it accesses the IPplatform 2 to receive the broadcast service. Thereafter, in step 926,the terminal searches access information of the IP platform 2 in thePSI/SI currently received from the IP platform 2 or scans neighboringsignaling, and searches access information for the broadcast service 1provided in the IP platform 2. In step 928, the terminal changes itsreception path to receive the broadcast service 1 provided from the IPplatform 2.

FIG. 10 illustrates an operation of a service provider in a broadcastingsystem according to an embodiment of the present invention.

Referring to FIG. 10, in step 1000, the service provider organizes ordesignates an IP platform 1 and an IP platform 2 as cooperating IPplatforms. In step 1002, the service provider will set related signalingvalues and parameter values, which are shown above in Tables 1 to 9, tosupport the cooperating IP platforms. In step 1004, the service providerdelivers a broadcast service to a terminal together with the signalingvalues and parameters as in Table 1 to Table 9. The service provider mayalso send the terminal a list of IP platforms having the common IPaddress range and an indicator indicating presence of the common IPaddress range in step 1004.

Above, the description has been made of the parameter values andsignaling values proposed by the present invention in accordance withTables 1 to 9 to receive the common broadcast service. In the followingdescription, the parameter values and signaling values proposed usingTables 1 to 9 will be referred to as related information relevant to thecommon broadcast service.

FIG. 11 illustrates architecture of a digital broadcasting systemaccording to an embodiment of the present invention. The digitalbroadcasting system includes a service provider 1100 and a terminal1150. The service provider 1100 in FIG. 11, which serves as a broadcastserver, provides a broadcast service and information related to thebroadcast service to the terminal 1150.

A PSI/SI generator 1102 generates PSI/SI for the terminal 1150 toreceive a broadcast service. In accordance with an embodiment of thepresent invention, the PSI/SI generator 1102 generates PSI/SI 1112 andsends it to the terminal 1150. A value No_IPPlatform for indicating anumber assigned in common to cooperating IP platforms among IPplatforms, an identifier Platform_id for identifying each cooperating IPplatform, and values Start_IPAddress and End_IPAddress indicating an IPaddress range for a broadcast service provided in common in thecooperating IP platform are inserted into the PSI/SI 1112. Because an IPplatform 1 and an IP platform 2 are organized herein as cooperating IPplatforms, the PSI/SI generator 1102 generates PSI/SI information forthe IP platform 1 and the IP platform 2 and sends it to the terminal1150.

An ESG generator 1104 generates an ESG for the terminal 1150 to receivea broadcast service. In accordance with an embodiment of the presentinvention, the ESG generator 1104 generates an ESG and sends it to theterminal 1150 through an ESG data model 1114 or an ESG bootstrap 1116. Avalue No_IPPlatform for indicating a number assigned in common to abundle of the cooperating IP platforms among IP platforms, an identifierPlatform_id for identifying each cooperating IP platform, and valuesStart_IPAddress and End_IPAddress indicating an IP address range for abroadcast service provided in common in the cooperating IP platforms areinserted into the ESG. Accordingly, the ESG generator 1104 generates anESG including the values shown in Tables 3 to 9, and sends it to theterminal 1150 to the terminal 1150 through the ESG data model 1114 orthe ESG bootstrap 1116.

An IP platform_1 1108 and an IP platform_2 1110 provide IP-basedbroadcast services 1118 and 1120 to the terminal 1150, respectively. Thebroadcast services 1118 and 1120 may include a common service.

A cooperating IP platform handler 1106 organizes specific IP platforms(the IP platform_1 1108 and the IP platform_2 1110 in FIG. 11) ascooperating IP platforms, and provides related information relevant tothe common broadcast service provided in the cooperating IP platforms(IP platform 1 and IP platform 2) to a related information transmitterthat includes the PSI/SI generator 1102 and the ESG generator 1104. Theterm “related information” as used herein refers to information about acooperation between the IP platform_1 1108 and the IP platform_2 1110paired as cooperating IP platforms. For example, the cooperating IPplatform handler 1106 generates the information shown in Tables 1 to 9,and provides it to the PSI/SI generator 1102 and the ESG generator 1104.In addition, the cooperating IP platform handler 1106 delivers broadcastservices provided from a content provider to the associated IP platforms1108 and 1110.

In accordance with an embodiment of the present invention, when there isa common broadcast service being provided in common in the cooperatingIP platforms, the cooperating IP platform handler 1106 assigns the sameIP address for the common broadcast service, generates relatedinformation relevant to the common broadcast service, and provides therelated information to the PSI/SI generator 1102 and the ESG generator1104. Then the PSI/SI generator 1102 transmits the related informationto the terminal 1150 together with the PSI/SI 1112, and the ESGgenerator 1104 transmits the related information to the terminal 1150through the ESG data model 1114 and the ESG bootstrap 1116.

The terminal 1150 acquires the related information needed to receive thebroadcast services 1118 and 1120, from the received PSI/SI or ESG, andreceives the broadcast services 1118 and 1120 from the IP platforms 1108and 1110 using the acquired related information, respectively.

After acquiring the related information including information about thecooperating IP platforms in this manner, the terminal 1150 determinesthe common broadcast service being provided in common in the IPplatforms, and receives broadcast data regarding the common broadcastservice while maintaining service continuity, in the process ofperforming a handover between the paired cooperating IP platforms. Inaddition, during the handover between the paired cooperating IPplatforms, the terminal 1150 may also receive the common ESG servicefragments for the common broadcast service in the cooperating IPplatforms while maintaining continuity.

As described above, the terminal 1150 receives related informationrelevant to a common broadcast service being provided in common in atleast two cooperating IP platforms, from one of the cooperating IPplatforms, and determines if the currently received broadcast service isthe common broadcast service, based on the related information. When thecurrent broadcast service is the common broadcast service, the terminal1150 continues to receive the common broadcast service from theremaining IP platform, except for the one IP platform.

FIG. 12 illustrates a structure of a terminal 1201 according to anembodiment of the present invention.

Referring to FIG. 12, a broadcast receiver 1203 receives a broadcastservice or signaling over a broadcast network. An interactive adaptor1205 receives a broadcast service or exchanges signaling over aninteractive network such as a mobile communication network. Asubscription management block 1209 manages right acquisition, tracks therights acquired for the terminal 1201, and controls decoding anddecryption on a received broadcast service. A content consumption block1211 provides the broadcast contents decoded and decrypted by thesubscription management block 1209 to the user.

In the network illustrated in FIG. 11, the related information definedin the present invention to support the cooperating IP platforms may becarried in the PSI/SI 1112, the ESG data model 1114 and the ESGbootstrap 1116.

In the terminal 1201, the PSI/SI 1112 is received by the broadcastreceiver 1203. The ESG bootstrap 1116 and the ESG data model 1114 arereceived by the broadcast receiver 1203 and the interactive adaptor1205, which constitute a reception unit.

Based on the PSI/SI 1112 received by the broadcast receiver 1203, thebroadcast services from the two IP platforms 1118 and 1120 are receivedby the broadcast receiver 1203 and the interactive adaptor 1205. Thatis, the related information relevant to the common broadcast servicebeing provided in common in the cooperating IP platforms and the commonbroadcast service are received by the reception unit.

A Mobility Management (MM) block 1207 may determine the IP platformsthat cooperate with each other or provide the same broadcast service,based on the PSI/SI or ESG received through the reception unit. The MMblock 1207 determines if the currently received broadcast service is acommon broadcast service based on the related information receivedthrough the reception unit. If the current broadcast service is thecommon broadcast service, the MM block 1207 acquires information neededto receive the common broadcast service from the related information,and controls the reception unit to continuously receive the broadcastservice from the remaining IP platform, except for the current IPplatform.

Based on this information, the terminal 1150 (1201) can continuouslyprovide the common broadcast service to the user, and the user candetermine whether to continuously receive the common broadcast service.

As is apparent from the foregoing description, according to theabove-described embodiments of the present invention, the digitalbroadcasting system provides broadcast service data to a mobile terminalthat has moved to another IP platform, while maintaining servicecontinuity.

While the present invention has been shown and described with referenceto certain embodiments thereof, it will be understood by those skilledin the art that various changes in form and details may be made thereinwithout departing from the spirit and scope of the present invention asdefined by the appended claims and their equivalents.

What is claimed is:
 1. A method for receiving a broadcast service in adigital broadcasting system, comprising: receiving, by a reception unit,related information relevant to a common broadcast service beingprovided in common in at least two Internet Protocol (IP) platforms,from one of the at least two IP platforms; determining, by a mobilitymanagement block, whether a currently received broadcast service is thecommon broadcast service, based on the related information; andcontinuously receiving the common broadcast service from a remaining IPplatform, except for the one of the at least two IP platforms, when thecurrently received broadcast service is the common broadcast service. 2.The method of claim 1, wherein the related information includes aplatform identifier including at least one of a first part having a samevalue in one group of cooperating IP platforms, which includes the atleast two IP platforms, and a second part having a value for identifyingeach of the at least two IP platforms included in the one group ofcooperating IP platforms.
 3. The method of claim 1, wherein the same IPaddress is assigned within an IP address range assigned for commonbroadcast services in an IP address range assigned to each of the atleast two IP platforms providing the common broadcast service.
 4. Themethod of claim 1, wherein the related information includes informationfor indicating whether the common broadcast service exists in the atleast two IP platforms.
 5. The method of claim 1, wherein the relatedinformation is delivered through at least one of a notification, ProgramSpecific Information/Service Information (PSI/SI), and an ElectronicService Guide (ESG).
 6. The method of claim 1, wherein an IP addressrange for each of the at least two IP platforms includes a common IPaddress range for the common broadcast service, and an IP address rangefor a non-common broadcast service.
 7. The method of claim 6, whereinthe related information includes a start IP address Start_IPAddress ofthe common IP address range and an end IP address End_IPAddress of thecommon IP address range.
 8. The method of claim 1, wherein the relatedinformation includes at least one of a field indicating whether anElectronic Service Guide (ESG)fragment for the common broadcast serviceis identical in the at least two IP platforms, and an identifier of anIP platform in which the identical ESG fragment for the common broadcastservice is used.
 9. The method of claim 8, further comprising acquiringan ESG fragment for the common broadcast service from the remaining IPplatform, when the ESG fragment for the common broadcast service is notidentical.
 10. An apparatus for receiving a broadcast service in adigital broadcasting system, comprising: a reception unit for receivingrelated information relevant to a common broadcast service beingprovided in at least two Internet Protocol (IP) platforms, from one ofthe at least two IP platforms; and a mobility management block fordetermining whether a currently received broadcast service is the commonbroadcast service, based on the related information, and for controllingthe reception unit to continuously receive the common broadcast servicefrom a remaining IP platform, except for the one of the at least two IPplatforms, when the currently received broadcast service is the commonbroadcast service.
 11. The apparatus of claim 10, wherein the relatedinformation comprises a platform identifier including at least one of afirst part having a same value in one group of cooperating IP platforms,which includes the at least two IP platforms, and a second part having avalue for identifying each of the at least two IP platforms included inthe one group of cooperating IP platforms.
 12. The apparatus of claim10, wherein the same IP address is assigned within an IP address rangeassigned for common broadcast services in an IP address range assignedto each of the at least two IP platforms providing the common broadcastservice.
 13. The apparatus of claim 10, wherein the related informationcomprises information for indicating whether the common broadcastservice exists in the at least two IP platforms.
 14. The apparatus ofclaim 10, wherein the related information is delivered through at leastone of a notification, Program Specific Information/Service Information(PSI/SI), and an Electronic Service Guide (ESG).
 15. The apparatus ofclaim 10, wherein an IP address range for each of the at least two IPplatforms comprises: a common IP address range for the common broadcastservice; and an IP address range for a non-common broadcast service. 16.The apparatus of claim 15, wherein the related information comprises: astart IP address Start_IPAddress of the common IP address range; and anend IP address End_IPAddress of the common IP address range.
 17. Theapparatus of claim 10, wherein the related information comprises atleast one of: a field indicating whether an Electronic Service Guide(ESG) fragment for the common broadcast service is identical in the atleast two IP platforms; and an identifier of an IP platform in which theidentical ESG fragment for the common broadcast service is used.
 18. Theapparatus of claim 17, wherein the mobility management block controlsthe reception unit to acquire an ESG fragment for the common broadcastservice from the remaining IP platform, when the ESG fragment for thecommon broadcast service is not identical.